Cable cutter

ABSTRACT

An emergency cable cutter in which opposed pistons are provided with overlapping cable-cutting blades. The blades have cablecutting openings therein through which the cable is threaded. Upon the application of pressure to the pistons they are driven toward each other causing the knife edges on the openings to sever the cable. Either of the pistons alone, can sever the cable in the event of failure of the other.

United States Patent lnventor Elmer Laky 56] References Cited Cranlord,NJ. UNITED STATES PATENTS pp 31,949 1,901,067 3/1933 Vickers 83/198 FMP4711970 3,089,368 5/1963 Cousino 83/198 x ""9"" 3,561,526 2/1911Williams,Jr. m1. 83/639 )1 Ass1gnees Breeze Corporation, Inc.,

U i NJ, Primary Exnmmer-Frank T. Yost Attorney-Albert F. Kronman CABLECUTTER SClalmaADrnving Figs. APSTRACT: An emergency cable outter inwhich opposed p1stons are provlded \vlth overlapplng cable-cuttingblades. us. 01 ..6 133/139, The blades have cablc cumng openings thereinthrough which 83/ the cable is threaded. Upon the application ofpressure to the 3 5 4 pistons they are driven toward each other causingthe knife 0 Search edges on the openings to sever h: cable Either of thepistons 5 1 1 alone, can sever the cable in the event of failure of theother.

1-111 1 Z? I 3d I 24 Q l CABLE CU'I'IER BACKGROUND OF THE INVENTIONWhere hoisting equipment is used in conjunction with helicopters and thelike, it is customary to employ steel cables for raising and loweringthe loads. In the event of emergency, it becomes necessary to sever thecable with speed and reliability. In multiple cable supported loads,such as four-point support, where failure to jettison all load pointssimultaneously may result in severe damage, the dependability ofcablesevering mechanisms becomes most critical.

In order to improve reliability, two independent cutters have beenmounted along the cable with the thought that, in the event of partialcable cutter failure, the second cutter would release the load. However,if the cutter located furthest the bell mouth of the hoist, partiallycuts the cable, the jammed cable often can support the load and theeffectiveness of the second cutter becomes nullified. In such event acatastrophic failure can occur.

In the present invention, a dual configuration cable cutter is providedin which two blades independently operated by opposed piston members cutthe cable at the same point, thus eliminating the possibility of thecable jamming in the hoist and causing severe damage.

In the accompanying drawing forming part hereof, there is illustratedone embodiment of the invention, in which drawing identical parts havebeen given the same reference numeral, and in which:

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a view in longitudinalsection of a complete embodiment of the present invention, shown in theprefiring condition.

FIG. 2 is a view similar to FIG. 1 showing the condition of theapparatus following the firing of the cable-severing mechanism.

FIG. 3 is a fragmentary sectional view taken on line 3-3of FIG. 1looking in the direction of the arrows.

FIG. 4 is a somewhat isometric view of the piston and cablecuttingportion of the device.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing andparticularly to FIGS. 1 and 2, indicates a cable-cutting device having asubstantially cylindrical housing 11 provided with a wall 12 at one endthereof and an internally threaded port 13 at its opposite end. A secondinternally threaded port 14 is cut into the sidewall 15 of the housing10 adjacent the end wall 12. The ports 13 and 14 are adapted to receivegas expansion driving means such as pressure cartridges 16 therein.

A pair of opposed piston members 17 are slidably received within thebore 18 of the housing 11. Each of the pistons are provided with sealingrings 19 to prevent the escape of gases between the pistons and thewalls of the bore 18 during firing.

The pistons are each provided with flat blades 20 which are cut out ofthe body of the pistons and which extend in the direction of the centerof the housing 1]. An arcuate upstanding wall 21 at the cable end of theblades 20 serves as a guide for the blade during firing.

It will be noticed from an examination of FIG. 3, that each of theblades 20 is provided with an opening 22 therein through which the cable23 is threaded. The edges of the openings 22 are beveled as indicated at24 to provide knifelike cable-severing blades. When the emergency cablecutter is assembled, as shown in FIGS. 1 and 2, the pistons and theblades are in opposed relationship with the flats 25 of each of theblades slidably resting upon the flat of the opposed piston blade.Shearpins 26 made of some suitable soft material are slipped through abore 27 in the housing 11 and into openings 28 in the pistons 17. Theshearpins prevent the edges of the blades 20 from coming into contactwith the cable 23 during nonnal operation of the hoist.

When it IS necessary to sever the cable 23, the pressure cartridges 16are fired by means of some remote electrical impulse (well known in theart and therefore not illustrated). Expanding gases within the chambers29, 30 between the ends of the pistons 17 and the pressure cartridges 16drive the pistons 17 toward each other thereby causing the knives 24 ofthe blades 20 to sever the cable 23. It will be noted that the cable 23is severed along the plane between the blades 20 and that in the eventone of the pistons I7 fails to move by reason of cartridge failure orthe like, the opposite piston will perform the necessary blade-severingoperation.

The condition of the piston assembly following cable severing will beseen in FIG. 2 in which the shearpins 26 have been cut and the knives 24brought into position where the opening 22 therebetween has beensubstantially closed.

From the foregoing it will be seen that there has been provided a highlydependable, compact, fail-safe cable-severing device which is free ofthe limitations of prior art structures.

Having thus fully described the invention, what is claimed as new anddesired to be secured by Letters Patent of the United States, is:

1. A cable-severing device comprising an elongated housing transverselybored to receive the cable therethrough, a longitudinal bore in saidhousing, opposed pistons, slidably carried within the longitudinal bore,a flat blade member on each of the pistons extending outwardly thereofin the direction of the opposed piston and in overlapping relationship,a cablereceiving aperture in each of the blades, a cable-severing edgeon each of the apertures and a pressure cartridge carried by the housingand in communication with each of the pistons to drive the pistons andtheir blades in the direction of the cable to sever the said cable.

2. A device according to claim 1 in which the ends of the bladesopposite the pistons are provided with arcuate upstanding guideportions.

3. A device according to claim I in which one end of the longitudinalhousing bore is closed by a wall, the opposite end of the bore is closedby the pressure cartridge and a bore is provided in the side of thehousing in communication with the longitudinal bore adjacent the endwall to receive a second pressure cartridge.

4. A device according to claim 1 in which the piston blades areprevented from accidental contact with the cable by shearpins carried bythe housing and received within radial bores in the said pistons.

5. A device according to claim 1 in which the cutting edges of theblades move along substantially the same plane during the severingaction.

i 8 I I

1. A cable-severing device comprising an elongated housing transverselybored to receive the cable therethrough, a longitudinal bore in saidhousing, opposed pistons, slidably carried within the longitudinal bore,a flat blade member on each of the pistons extending outwardly thereofin the direction of the opposed piston and in overlapping relationship,a cablereceiving aperture in each of the blades, a cable-severing edgeon each of the apertures and a pressure cartridge carried by the housingand in communication with each of the pistons to drive the pistons andtheir blades in the direction of the cable to sever the said cable.
 2. Adevice according to claim 1 in which the ends of the blades opposite thepistons are provided with arcuate upstanding guide portions.
 3. A deviceaccording to claim 1 in which one end of the longitudinal housing boreis closed by a wall, the opposite end of the bore is closed by thepressure cartridge and a bore is provided in the side of the housing incommunication with the longitudinal bore adjacent the end wall toreceive a second pressure cartridge.
 4. A device according to claim 1 inwhich the piston blades are prevented from accidental contact with thecable by shearpins carried by the housing and received within radialbores in the said pistons.
 5. A device according to claim 1 in which thecutting edges of the blades move along substantially the same planeduring the severing action.